The present invention relates to a thermal comfort sensor device of the kind defined in the preamble of claim 1, usable in particular for evaluating the sensation of warmth perceived by an occupant of the passenger compartment of a motor vehicle.
The perception of body warmth is dependent on heat exchange between the human body and the surrounding environment. The human body tends to dissipate the heat generated by its metabolism. The physiological reactions (vasodilatation, vasoconstriction, sweating etc.) that take place in order to regulate the flow of heat exchanged between the body-and the environment can cause thermal discomfort.
U.S. Pat. No. 5,560,711 discloses a sensor device of the above-identified kind comprising two diaphragms, each forming a central membrane with 2 to 3 μm thickness, bonded to one another through an adhesive to form an air cavity therebetween. The membrane of the lower diaphragm includes a thin film heater and a thin film temperature sensor. The membrane of the upper diaphragm includes two series-connected thermocouples operating to sense a skin temperature condition, a room temperature sensor and a black body layer formed on the latter. The sensor device provides in use an output voltage which depends on the air flow rate.
DE-39 22 854-A1 discloses arrangement for providing a measure of thermal comfort in an environment having a conditioned climate. The arrangement includes separate sensors applied in specific locations on an anthropomorphic dummy. Said sensors include air flow speed sensors.
In order to evaluate heat sensation in a particular environment, such as the passenger compartment of a motor vehicle, anthropomorphic dummies with sensors have been proposed and manufactured which are able to measure the values assumed by certain predetermined physical quantities which contribute to the perceived heat sensation. Such dummies are usually jointed so they can be arranged in typical postures of the driver or passengers of a motor vehicle.
In the passenger compartment of a motor vehicle, or in any seated position, the human body exchanges heat through contact with the seat and with the surrounding air.